/*

abstract class Shape {
    public int a = 10; //抽象类可以定义成员变量和成员方法
    public Shape(){
        //构造方法
    }
    public abstract void draw();
}

class Rect extends Shape {
    @Override
    public void draw() {
        System.out.println("♦");
    }
}

class Cycle extends Shape {
    @Override
    public void draw() {
        System.out.println("●");
    }
}

class Triangle extends Shape {
    @Override
    public void draw() {
        System.out.println("▲");
    }
}


public class Test2 {
    public static void main(String[] args) {

        //Shape shape = new Shape(); // 编译出错
        //Error:(30, 23) java: Shape是抽象的; 无法实例化
    }
}
*/
